Chemotherapy is a chemical treatment used to kill cancer cells that also suppresses – or stops – the body's immune system from working.

化疗是一种杀死癌症细胞的化学疗法，也会抑制人体免疫系统。

He said it is a good idea to be thoughtful and find a natural way to fight insects before using a chemical treatment.

他说，在使用化学处理之前，最好深思熟虑，然后找到一种自然方式消灭害虫。